Project

Motivation

Traffic on cellular wireless networks is growing rapidly due to increases in data, streamed high-bandwidth video and digital TV. The networks themselves have typically not been planned for such traffic, so that mobile operators have some difficult decisions to make if they are to maintain good user experience. Since the proportion of voice traffic as a function of the total is becoming less, the revenue generated is not in proportion with the traffic increase and the gap between traffic growth and revenue will get larger. A second factor is that European countries typically have multiple cellular operators who are no longer able to differentiate themselves on coverage. The combination of these factors is resulting in radio base-station sharing to reduce costs (for example T-Mobile and 3 in the UK1 and Telefonica and Vodafone pan-European collaboration to share network infrastructure in Germany, Spain, Ireland and the Czech Republic).

In parallel, a regulatory trend is that radio spectrum is moving towards technology and service neutrality where several user groups have access but are required to work out their own mechanisms to manage interference. One example of this neutrality (but still with licensed spectrum) is the central portion of the 2.5–2.7GHz band to be auctioned in the UK in 2010. Another example of neutrality, but coupled with opportunistic use of spectrum has arisen from television switching from analogue to digital in both the US and Europe. From this activity, TV ‘white spaces’ are increasing in the US and also spectrum is becoming available in Europe through the ‘digital dividend’.

Making use of technology and service neutral spectrum opportunistically is a principal focus of QoSMOS.

Low power cognitive devices could potentially share with radar if the radar sweep can be detected and the transmission of the timed to avoid interference. This scheme would involve sharing on a dynamic temporal basis where the opportunistic user would need to have cognitive equipment that adapts to spectrum measurements.

The opportunistically obtained spectrum can be used for congestion relief during peak loads in licensed spectrum, or to enhance existing services and / or provide new services without the need for acquiring additional licensed spectrum. More generally, with the availability of opportunistic spectrum access telecommunication and digital broadcasting systems will be able to dynamically and locally vary their operating spectrum over a wide range of frequencies bands, and access the best available spectrum on a ‘just-in-time’ basis. This may happen either upon instruction from a cognitive base station or autonomously by devices themselves.

Good user experience at the right price is a key to the commercial success of services, and will be one of the cornerstones for the future internet, but this will require support for managed QoS and mobility.

The value chain currently in place for mobile broadband, which benefits a comparatively low number of operators and service providers, is likely to continue with LTE and IMT-A mobile services if unchallenged. Lowering the barriers to market entry for service providers, at present restricted to fixed networks, should be further extended to mobile networks. This will encourage growth of entrepreneurial service providers and supply new employment prospects. The market for vendors will expand beyond the low number of operators, on whom they are dependent for custom and are nervous about upsetting, to customers of new market entrants which will herald increasing production and faster development cycles.